In a blog post on ATR’s website, the group states that a vote for Plan B, which could come up as early as Thursday, will not be a violation of the pledge.

“This legislation — popularly known as “Plan B”— permanently prevents a tax increase on families making less than $1 million per year. Republicans supporting this bill are this week affirming to their constituents in writing that this bill — the sole purpose of which is to prevent tax increases — is consistent with the pledge they made to them. In ATR’s analysis, it is extremely difficult — if not impossible—to fault these Republicans’ assertion.”

ATR argues that because House Republicans have “already voted twice to prevent any tax increases on any American” and because the bill “contains no tax increases of any kind” it would not be a pledge violation. Boehner’s bill permanently extends the Bush tax cuts for those who make less than $1 million, and would simply let taxes go up for those above that threshold by letting them expire.

President Barack Obama has said he will veto the Plan B bill should it reach his desk.

“The Heritage Foundation explains that such a ‘maneuver succeeds only if the House Republican leadership permits it.’ Moreover, decoupling the 2001- and 2003-era tax rates would ‘constitute a clear path toward surrender on conservative principles,’” they added. ”Taking money out of the private sector to fund the public sector is not only misguided, it is counterproductive.”